Means for fastening electrode systems in braun tubes



ERSKA Sept. 5, 1939.

MEANS FOR FASTENlNG ELECTRODE SYSTEMS IN BRAUN TUBES Filed July l, 1956MW FW www Patented Sept. 5, 1939 PATENT OFFICE MEANS FORFASTENINGELECTRODE sYs- TEMs 1N BRAUN TUBESV Ernst Ruska,Berlin-ZehlendorLGermany, as-

signor tothe rm Fernseh Aktiengesellschaft, Zehlendorf, near Berlin,Germany Application July 1, 1936, Serial No. 88,486 In Germany July 9,1935 2 Claims.

The invention relates to means for mounting in the interior of electronray tubes the electrode systems used therein and especially theaccelerating control and intensity control systems used 5 in imagescanning and image reproducing tubes.

In making Braun tubes the problem arises of firmly positioning theelectrode system as a unit prior to fusing the cathode in place, and, ifrequired, the Wehnelt cylinder.

1o In order to fasten the electrode system with simple connecting meansbut in an accurate manner in the neck of the tube, the neck of. thetube, in accordance with the invention, is provided either with aninwardly pressed groove or i3 outwardly extending protuberance extendingannularly around the neck or else with inwardly extending depressions oroutwardly formed proturberances disposed in one or more locations in thesame or different planes perpendicular to the 2O axis of the tube. Aconical or cylindrical stud may also be arranged to extend inwardly.Springsare laid in r over the grooves or proturberances, said springsbeing associated with a portion of the electrode system and tting posi-25 tionally accurate into the groove when the springs are provided Wtihcooperating depressions or cross-grooves. If proturberances or: studsare provided on the wall of the neck the hole in the spring, when theelectrode system is 30 inserted, snaps into engagement over such studs.Inwardly extending grooves or proturberances have the advantage that theexterior of the tube remains smooth. This makes it possible to permitthe exterior cross-deflecting and collector a5 system to be snuglyapplied to the neck of the tube.

A single stud has the advantage that care need be taken only withrespect to its axial position. In providing a plurality of peripherallydistrib- 40 uted studs the angular separation must be careiullyconsidered Yand this renders the production more diiiicult. However,this system eiects a more rigid seating of the system in the neck of thetube.

45 The electrode system, which, `for example consists of the anode tube,Wehnelt cylinder, and cathode, rests, in accordance with the inventionin resilient fashion against the neck of the tube and hence, in mostcases, also against the con- 50 ducting interior coating of the neck,and in such a manner that the indented groove positionally retains thesystem in axial relation or else the stud not only axially positions itbut also insures it against turning. Both factors are important,

55 in order, for example, when the cathode and (Cl. Z50-141) Wehneltcylinder are fused in place, to make sure that no subsequent positionalchange occurs owing to the forces acting on the system, (such asgravity, traction caused by the glass, etc). The resilient portions,such as leaf springs, o-r a 5 spreading ring, may be fastened to anydesired portion of the electrode system, e. g. to the periphery of atube, to a diaphragm, or to an insulating portion. The anode voltage insuch a tube may be led in by known means, either through a separatelead-in disposed on the side of the tube leading to the interior coatingof the tube, or through the base of the tube (e. g. in the case ofsingle socket mounting).

In the accompanying drawing:

Fig. 1 shows a means for fastening the electrode system to the neck ofthe tube in accordance with the invention.

Fig. 2 is a section on line A-B of Fig. 1.

Fig. 3 is a spreading ring electrode as used for 20 fastening theelectrode system tothe neck of the tube.

Fig. 4 is a top view of Fig. 3.

Fig. 5 shows a tube neck provided with internally directedprotuberances.

In Fig. 1 the numeral i designates an anode tube with the anode 2disposed therein. An insulating connecting member (screw ring) 3 isscrewed into the upper end of the anode tube, said ring being adapted toeffect the accurate coaxial positioning of the cathode or Wehneltcylinder 4 and anode tube I. 5 is the pressed foot of the tube. Theanode tube l carries three leaf springs 6 distributed in 120 separationsaround its periphery and which extend in the axial direction of thetube, said springs however being bent off at an angle from the anodetube at both ends and carrying a slightly curved portion directedtowards the anode tube. The springs are fastened to the anode tube bymeans of two or more screws, rivets, or spot welds lying within theangularly bent off free resilient ends. At least one of the springs hasan opening which engages over the protuberances 'l on the glass wall 8.The material of the spring must be completely non-magnetic and must notlose its elasticity during the usual making temperatureschromium-nickel, contracid-beryllium alloys, etc. being suitable). Thesame requirements are indicated for the material of which the spreadingring electrode described below its made. Obviously other portions of theelectrode system,

e. g. the individual electrodes or deflecting plates or deiiecting coilsas well as electrode supports and lead-ins or even insulating portionswith which the remaining system is rigidly connected may be providedwith springs and supported in the described manner in the neck of thetube so that they aid in retaining the remainder of the system.Likewise, springs may be distributed around the periphery in a pluralityof different planes (especially two planes) perpendicular to the neck,said springs under certain conditions being of different potential whenattached to different electrodes.

'Ihe spreading ring electrode 9 shown in Fig. 3, for example an anode,may be provided like the individual springs, with one or more holes ordepressions into which the studs or protuberances engage and thus serveto hold them in place. However, the spreading ring may cooperate withone or more internal studs l0 of the neck after the fashion of a bayonetfastening. For this purpose the ring is then provided with one or moreright angle slots H.

The cross yoke I3 which serves for holding the anode diaphragm I2 isbent out from the spreading ring at right angles to the ray axis andtube axis, or is fastened at right angles to the spreading rings, e. g.by Welding or riveting.

In Fig. 5 the tube neck 8 is provided with a protuberance I5 over whichthe springs 6 of the anode tube I snap. The fastening means of theinvention is especially applicable to tubes in which the deiiectingsystem consists of coils which are forced exteriorly over the neck ofthe tube. However, it is also possible to dispose the complete electrodesystem inside the tube without difliculty. Nevertheless `in that case itis preferable to provide not only one spring which engages in astud orgroove, but rather a plurality of springs which, if desired, may also beattached to different parts of the electrode system.

I claim:

1. In a tube of the Braun type, an envelope having a protuberanceprojecting inwardly thereof, a source of electrons adjacent an end ofsaid tube and on the axis thereof, elongated anode structure in saidtube, means for mechanically coupling said anode structure at one endwith said source of electrons to form a unitary electrode assembly,means for anchoring said electrode assembly at the aforementioned end ofsaid tube, and spring means disposed about said anode structure incontact with said tube and engaging said protuberances for alining theremainder of said elongated anode structure with said source ofelectrons along the axis of said tube and maintaining said anode againstdisplacement while in the process of assembly.

2. In a tube of the Braun type, a source of electrons adjacent an end ofsaid tube and on the axis thereof, elongated anode structure in saidtube, means for mechanically coupling said anode structure at one endwith said source of electrons to form a unitary electrode assembly,means for anchoring said electrode assembly at the aforementioned end ofsaid tube, a protuberance on the inner Wall of said tube and means 'foralining the remainder of said elongated anode structure with said sourceof electrons along the axis of said tube and maintaining the sameagainst displacement during the process of assembly comprising aplurality of leaf springs disposed about and attached to said anode andhaving free ends contacting the inner wall of said tube with at leastone of said leaf springs interlocking with said protuberance.

ERNST RUSKA.

